Currently, some electronic devices on the market have their dust-resistance and water-resistance as selling points. For example, an electronic device such as a mobile phone may be rated as “IP67,” where IP stands for the International Protection marking, a standard drawn up by the International Electrotechnical Commission (IEC) and indicative of the protection capability of the electronic device to be resistant to liquid and solid particles. The first digit 6 in “IP67” stands for a resistance of the electronic device to solid particles such as dust, i.e., a rating for “no ingress of dust; complete protection against contact,” in other words ‘dust tight.” To achieve such a rating, the electronic device needs to be configured such the gaps of outer shells of the electronic device are smaller than the diameters of typical dust particles. The second digit 7 stands for a resistance of the electronic device to liquid, such as water, in the case of immersion in the liquid with a depth of up to 1 meter for a short period of time (for example, 30 minutes). With no other special requirements, IP67 represents a highest rating for protection.
In order for an electronic device to reach a protection rating of IP67, the treatment of ports of the device is considered to be the most important aspect. For example, a headset and/or microphone port, such as a port on a mobile phone for connecting to a headset, needs attention in the design of the mobile phone. To prevent water from entering through the headset port, one approach is to completely block the port of the headset assembly, leaving only contacts (i.e., electronic contacts) being connected with the headset port.
Because the headset port is independently isolated from the main components and the motherboard, even under situations where water enters the headset port, the water cannot enter the inside of the mobile phone to damage the motherboard and other main components of the mobile phone.
One disadvantage of this above approach is that it has a high requirement of the manufacturing process. Especially because a headset assembly typically comprises a metal material and a plastic material, the control over manufacturing precision is very difficult due to the different thermal expansion and contraction properties of the two very different materials; and if gaps are configured to be too small, it is not easy for assembly. If a single molding process with a metal-plastic mold is adopted, there is a high requirement for the design, increasing the manufacturing cost.
In addition, as for the aforementioned closed-type of headset port, the level of water-resistance does not provide water protection to the headset port itself. If water has contacted the contact points inside the headset port, the headset cannot be used for at least a short period time. If the contact points are in water for a long period of time, the water can erode the contact points and adversely affect the transmission of audio signals.